This invention relates to a protective sheath for use with laparoscope, and is more particularly concerned with a sterile sheath for a laparoscope that contains an imaging device in the distal tip of its insertion tube, and carries a fiber optic bundle or similar illuminating means that emits light from the distal tip of the insertion tube.
A laparoscope is a device for observing the inside of a body cavity and permits surgical techniques to be carried out in a minimally invasive manner, i.e., through a small slit or incision in the patient.
The laparoscope has an insertion tube, which is generally a rigid elongated member that contains a miniature video camera or other imaging device at its distal end, and also contains a fiber optic bundle which carries illumination forward to illuminate a target within the patient's body cavity.
Because the surfaces that contact the patient must be completely sterile, a sterile sheath can fit over the insertion tube to isolate the insertion tube itself from contact with the patient.
One proposal for a disposable protective sheath is described in U.S. Pat. No. 4,741,326, where the sheath has the form of a flexible envelope that unwraps or unfolds over the probe tube. Another cover for an endoscope device is described in U.S. Pat. No. 5,154,164. An instrument cover of elongated cylindrical design is described in U.S. Pat. No. 4,886,049. A heat sterilizable rigid cylindrical sheath is described in U.S. Pat. No. 4,878,485.
In copending patent application Ser. No. (Attorney Docket No. 286 P 014), assigned to the assignee of this application, it is recognized that the light emitted from the illumination fiber optic bundle can reflect and scatter on surfaces of the sheath face plate. This can cause undesired flare in the optical or video image, and can impair image quality.
Contamination of the instrument can occur because of the patient's body fluids. These can contact not only the insertion tube, but also the handle, umbilical, and even the modular plug that couples the probe to a light box, monitor or other equipment. Accordingly, the sheath should include means to shield the entire probe from contamination. On the other hand, the disposable sheath should be configured in a way that minimizes risk of exposure of the health care or surgical workers to the surfaces contaminated by body fluids when the disposable sheath is removed after surgery.
A sterilizable sheath that includes an accordion-folded expandable portion is described in Adair U.S. Pat. No. 4,878,485. The expandable portion is an elastomeric material bonded to the rigid tubular part of the sheath and is intended to be pulled back to cover the flexible cord, or umbilical, of the instrument, and is retracted after surgery for removal from the probe insertion tube.
However, the accordion-folded portion always has the same side exposed to the outside, such that when the sheath is removed after a surgical procedure, the surface contaminated by contact with the patient's body fluids is still on the outside. This presents to the surgeon, nurse, and other clinical and hospital workers a significant risk of contact with these fluids.